Abstract: A rapid method for generating a set of discrete DNA amplification products characteristic of a genome as a "fingerprint" comprises the steps of: priming target nucleic acid of a genome or from a cellular RNA preparation with an single-stranded primer to form primed nucleic acid such that a substantial degree of internal-mismatching occurs between the primer end the target nucleic acid; amplifying the primed nucleic acid by performing at least one cycle of polymerase chain reaction amplification; and amplifying the product of step (2) by performing at least about 10 cycles of polymerase chain reaction amplification. The method is known as the arbitrarily primed polymerase chain reaction (AP-PCR) method and is suitable for the identification of bacterial species and strains, including Staphylococcus and Streptococcus species, mammals and plants.